Move existing kSitePerProcess checks to a policy-oracle object

components/guest_view/browser/guest_view_base.cc

Index: components/guest_view/browser/guest_view_base.cc
diff --git a/components/guest_view/browser/guest_view_base.cc b/components/guest_view/browser/guest_view_base.cc
index cffdd572065685564bcb1029d6e9e468e985be4a..b197a1269a7b1fd578929858583b64bcba7d8d8f 100644
--- a/components/guest_view/browser/guest_view_base.cc
+++ b/components/guest_view/browser/guest_view_base.cc
@@ -4,7 +4,6 @@
 
 #include "components/guest_view/browser/guest_view_base.h"
 
-#include "base/command_line.h"
 #include "base/lazy_instance.h"
 #include "base/strings/utf_string_conversions.h"
 #include "components/guest_view/browser/guest_view_event.h"
@@ -19,8 +18,8 @@
 #include "content/public/browser/render_view_host.h"
 #include "content/public/browser/render_widget_host_view.h"
 #include "content/public/browser/web_contents.h"
-#include "content/public/common/content_switches.h"
 #include "content/public/common/page_zoom.h"
+#include "content/public/common/site_isolation_policy.h"
 #include "content/public/common/url_constants.h"
 #include "third_party/WebKit/public/web/WebInputEvent.h"
 
@@ -571,8 +570,7 @@ void GuestViewBase::DidNavigateMainFrame(
   // TODO(lazyboy): This breaks guest visibility in --site-per-process because
   // we do not take the widget's visibility into account.  We need to also
   // stay hidden during "visibility:none" state.
-  if (base::CommandLine::ForCurrentProcess()->HasSwitch(
-          switches::kSitePerProcess)) {
+  if (content::SiteIsolationPolicy::GuestsShouldUseCrossProcessFrames()) {
     web_contents()->WasShown();
   }
 }